Sky News has a particularly fast rolling graphics service. Funding public service broadcasting The main terrestrial television channels available in all homes are regu- lated by Ofcom.
They have to provide elements of public service broad- casting. For the commercial channels there is an obligation to provide a regular, quality news service throughout the day. There are other require- ments to do with programmes for minorities. A bone of contention for ITV1 is that they are required to broadcast regular religious programmes, and Ofcom has indicated that it may drop this requirement in the future.
Public service broadcasting 17 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 Figure 3. The BBC 21 is the only public service broadcaster with no commercial funding. It is 22 funded by the licence fee. There have been many attempts to invent an 23 alternative source of funding for what is seen by some as a retrogressive 24 compulsory tax. Other countries such as New Zealand have scrapped the 25 licence fee, and fund all channels with advertising. This has not led to a 26 better service for the viewers.
Some European countries keep a smaller 27 licence fee and allow some advertising for their public service channels. This guarantees the independence of the BBC and particularly 33 its news and current affairs. Alternative sources of funding include a 34 subscription service. This is how the public service channels in the US 35 are funded, often woefully inadequately. Another idea is to top slice the licence fee, and give some of 38 the money to other broadcasters who have a public service remit.
There is the risk that public money would benefit shareholders rather than licence payers. Another idea that is often floated is that the BBC should accept advertising. This would reduce the licence fee according to the amount of revenue generated by advertising. The main argument against this is that the revenues of the commercial broadcasters, particularly ITV, Channel 4 and Five, would be severely reduced.
Other suggestions include a govern- ment grant, rather like a grant to an arts institution such as the National Theatre. It is very difficult to find a better way of funding a public service such as the BBC.
There is no doubt that BBC services are very popular, reaching over 98 per cent of the UK population every week. Surveys show that viewers prefer radio and television programmes that are not interrupted by adver- tising. The BBC website with over 2 million pages is one of the most popular in the world, continually winning awards.
This is grainy and lacks impact. Colour television with a resolution of lines was introduced in the s, 18 and the sharper picture and startling realism of colour was instantly a huge 19 success, providing not only a boost for manufacturers but also for the BBC.
Current digital technology is also generating changes in 23 all areas of television. Programmes are shot in widescreen format with dig- 24 ital cameras, edited with digital postproduction software on a computer, and 25 transmitted in widescreen format using digital transmission systems. The 26 benefits of recording television pictures in a digital format are enormous 27 including impressive quality, more compact storage, ease-of-use with more 28 possibilities in postproduction.
More and more productions are being made 29 in the next generation of digital equipment known as HD — High Definition. This means that the way we receive our television pictures 37 through an aerial will change, but this will hardly affect the consumer.
Freeview is as its name suggests free, apart from the modest one-off cost of a set-top decoder box. Where households cannot receive Freeview the BBC is proposing to collaborate with other suppliers to supply free TV via satellite.
Sky has already announced a Freesat service. This is very attractive to the government who would like to sell off the analogue channels currently used for TV transmission. The BBC is at the forefront of this digital revolution. In its manifesto for the future published in June in the lead-up to the renewal of its Charter in , the BBC says it intends: to be at the leading edge of the new era and is building its case on free services.
The BBC says it can help the UK become a fully digital nation because of the appeal of its content, and the trust the public has in its brand. Some people think the BBC is too large, and should only offer a narrow range of services. The BBC is putting a large emphasis on education. In , the BBC with commercial partners will launch an online digital curriculum. This will cover the key elements of the school curriculum, and be made available, free, to every school in the UK.
Digital technology The term digital refers to the fingers and thumbs used in ancient times for counting, and is associated with whole numbers. These data can be encoded in a series of electronic pulses, and in elec- 4 tronic circuits such as are found in a computer, switches are either on or 5 off. Data that are encoded digitally have distinct values allowing no vari- 6 ables. To make a number of value greater than one, combinations of binary 7 digits are used, known as bits.
For example, two bits give four combina- 8 tions of ones and zeros: 00, 01, 10, Eight bits have combinations 9 of ones and zeros. So it is possible to build up a digital stream of numbers 10 that represent any value. With 12 digital technology more data can be transmitted over the same physical 13 links.
These links can be cables, fibre optics, satellite or TV transmission. They are more accurate, with more data being transferred in shorter 16 times. There are many important advantages of using digital technology 17 in television and video.
It allows audio and video recording with none 18 of the electronic noise or distortion found using tape analogue systems. Pictures and sound recorded as digital data can be 21 manipu-lated for an extraordinary variety of video effects, from wipes and 22 dissolves to computer-generated animation CGA found in films such 23 as The Lord of the Rings. Digital technology is now standard through- 24 out television production, from recording through postproduction to final 25 transmission.
A prism inside the lens barrel splits incoming 35 light into the primary colours, red, green and blue RGB. Each colour 36 goes to a different CCD. This gives superb colour reproduction and image 37 quality. Cheaper cameras have just one CCD. This is fine for domestic 38 camcorders, but does not give a high enough resolution for broadcast TV. Pixels vary in quality and 2 capability.
It is not always true that the more pixels in a digital camera 3 or camcorder, the better the picture resolution. The sound is usually encoded into bit PCM pulse code modu- 9 lation and sampled at 44, Hz. This is the configuration most commonly 10 used for compact discs.
Hertz, or cycles per second, is a measurement of 11 the frequency, or pitch, of sound waves. Orchestras tune to the note A, 12 which has a frequency of Hz. The physical sound waves produced, 13 by the voice of a TV presenter for example, are picked up by a micro- phone. The sound is sampled by using PAM pulse amplitude modula- 15 tion. This means the amplitude of the waveform is measured many 16 thousands of times a second to produce a digital value that can be stored 17 on tape, CD or DVD.
A typical bit sample will have 65, levels of 18 clarity. This can be read and reconfigured as electrical waves that can be 19 heard through a loudspeaker. Digital 22 data are measured as electrical pulses, either on or off. Therefore, the 25 26 copy of a master recording will be a precise clone of the original recording. This is an 28 extremely fast process that does not need to be done in real time, as making 29 analogue copies does, and uses less space. Using high-end microphones 30 and recording equipment — such as a Nagra digital recorder — the recorded 31 sound has impressive clarity and fidelity to the original.
There is no elec- 32 trical noise or hum, and the equipment can be light in weight. Even using 33 inexpensive kit, digital recording offers clarity, portability and easy transfer 34 of data to formats such as MP3 or minidisc. Similarly a television camera converts the colour and brightness information of the moving image into electrical signals that can be trans- mitted to TV receivers at home, or recorded in a digital domain on tape, disc or computer.
These television signals are converted into frames of data, and projected at a rate fast enough so that the human eye perceives continuous motion. Each separate frame is drawn line by line, from top to bottom. Using a typical European 50 hertz alter- nating current, it draws 50 lines per second, but it takes two passes to draw a complete frame.
The frame rate is therefore 25 frames per second fps. This system uses lines and runs at 30 fps, and was developed from the electric current used in the US, which alternates at 60 hertz. The widescreen world of digital technology 25 These are all analogue systems. Sky TV already transmits only in digital format.
An 12 analogue to digital converter ADC will convert analogue signals into 13 binary data. As in digital sound recording the process is achieved by sampling. This is also known as video capture. To view digital video on 15 a traditional television set, the process has to be reversed. A digital to 16 analogue converter DAC is required to decode the binary data back into 17 an analogue signal that a domestic TV can understand.
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Basic Principles of Digital Television Transmission. Back Matter Pages About this book Introduction This practical reference book is concerned mainly with the technology of digital terrestrial television broadcasting. The author describes the latest developments in digital television, the status of analog technology, and the basics of digital technology and its specifications.
The operating and measurement procedure is given especially extensive treatment. Technical future scenarios are also discussed.
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